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Discussion Starter · #1 ·
I like to toy with the idea of doing a supercharger install on my Soltice in the future should a good kit becomes available. My question is, if I put a supercharger system on, can I still pass smog inspection in CA? My understanding is that all the original equipment must be there to pass.
 

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fwiw..the magnuson supercharger kit for corvettes has a CAFE smog number so it can be installed on corvettes and still pass california emissions.

Not all s/c manufacturers go through the expense and hassle so its a toss up on whether the solstice kit that might come out will be california legal.

Just an fyi and a suggestion it might be better to wait until next year when GM offers the s/c right off the showroom floor.
 

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Discussion Starter · #3 ·
JBsZ06 said:
Just an fyi and a suggestion it might be better to wait until next year when GM offers the s/c right off the showroom floor.
That might be best, but it seems as though Pontiac is headed in the turbo direction not supercharger. I'm really not intersted in a turbo, also I'm not all that crazy about the cosmetic changes they are planning to do to the base Solstice. I personaly prefer the look of the one I have now. Thanks for the info on the Vette systems. I hope that a Solstice system comes out like this someday.
 

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Carb approval is a fun process but it isn't that big of a deal. You just need to pay a bit and get a car to Cali to get tested.

Remember, a turbo is going to make 20% more power with a larger power curve compared to a supercharger. You'll also get a lot better gas mileage with a turbo versus a supercharger.

And no the GXP won't look like the club racer with the wing, vents, etc..
 

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A supercharger will get you more power under the curve than a turbo, dollar for dollar. Just ask the big-time drag racers who use them religiously. And a supercharger gets better gas mileage because instead of being an exhaust obstruction at cruising speed, it increases volumetric efficiency above 100% at cruising speed... My GTP got 33mpg averaged on a 2500+ mile trip.

Not that I'm really disagreeing with you, just that the SC/turbo argument has been around for ages and nobody ever wins.... ;)

For the best of both worlds, go twincharged!

As far as Carb testing in CA, I thought you had to have all emissions equip, and pass the test. Pretty sure that means all oxy sensors, egr system, and cat. Not sure if anything else is included, though. All of that is retainable if the aftermarket kit is designed right.
 

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Sky Captain, your just flat out wrong buddy. Please don't be offended I like you and I'm not trying to be a jerk. Please remember that this is my back ground.

The parasitic power loss from a supercharger is much greater then the back pressure created by a turbo- I've measured both first hand. My car has a fairly small turbo and I see a horsepower gain of 20.5 horses per pound of boost.

Comparing a Procharger Supercharger the Procharger gained 17.5 horses per pound of boost, 16% less power. The difference is the mechanical force used through the gear reduction to spin the blower. The turbo doesn't use any type of a gear reduction; it just spins with the exhaust pressure that is already there. A turbo feeds off itself, it uses back pressure to create boost and as it creates more back pressure it creates more boost. With out a waste gate a turbo would be more then happy to make 30 PSI and blow your motor. A supercharger is severely limited by slipping belts and volume. A magnuson supercharger makes decent power down low but totally falls off up on top end when you try and run more then 7 PSI. Why do you think the SS Cobalt has 200 horsepower with a supercharger and the turbo Solstice will have 245 horsepower with the exact same motor???

Essentially the supercharger needs 1.80 PSI just to get it back to where it was stock. A turbo needs .35 PSI to get it back to where it was stock. Because the turbo creates a lot of torque sooner in the power band and because it doesn't add an engine load you get better gas mileage. For example the Porsche 911 Turbo gains 119 horses over a non turbo 911 with only a 3/4 MPG drop, the SS Cobalt has a gain of 55 horses over the regular Cobalt but it loses 2/5 MPGs.

Top Fuel dragsters use roots blowers because of the required volume and cost. It wouldn't be too cost effective to build a 300 millimeter turbo to handle that much power. The world's fastest door slammers are turbo cars now. The world's fastest 4 cylinders are all turbo ecotecs. 99% of all forced induction motors use turbos thanks to modern diesel technology.

Check out this graph from Hot Rod Magazine:

"Given equivalent vehicles, the turbo would easily motor away from the centrifugal in an acceleration contest......The turbo offered massive midrange torque production, the only system to exceed 600 lb-ft. Need more convincing? At 4,000 rpm, the turbo was more than 100 lb-ft. stronger than either the Roots or centrifugal." Richard Holdener, "Battle of the Boost"
 

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bradyb said:
Sky Captain, your just flat out wrong buddy. Please don't be offended I like you and I'm not trying to be a jerk. Please remember that this is my back ground.
Not offended, but I'm definately not "flat out wrong". You are not the only one with this kind of background - and frankly, I'm not so impressed by your background, or more specifically, the company you developed that background with. Please don't be offended by that remark. But your background is primarily with STS and rear mounted turbo systems. I remember when you first came on here that STS and RMTSs were the second coming of Christ and the answer to all Solstice performance needs. But now that you're now longer in the STS camp things have changed, more than slightly. I was never impressed with STS and the RMTS crowd or the results, when compared to other kits available for a given platform. Although, I must admit, the ease of adding an RMTS is a meaningful point for the DIY installer.

The parasitic power loss from a supercharger is much greater then the back pressure created by a turbo- I've measured both first hand. My car has a fairly small turbo and I see a horsepower gain of 20.5 horses per pound of boost.
While that is true for peak horsepower, it means absolutely zip before that turbo spools up. When your turbo isn't spooled up (for example when CRUISING as I said above) it's nothing but an exhaust obstruction. A supercharger, on the other hand, continues to force air through the system even at cruising speeds, causing the AE & VE to be above 100% in many applications but always an improvement, sans bypass systems. Hence: my very valid assertion that superchargers can increase your gas mileage at cruising speeds while a turbo reduces it in most applications.


Comparing a Procharger Supercharger the Procharger gained 17.5 horses per pound of boost, 16% less power. The difference is the mechanical force used through the gear reduction to spin the blower. The turbo doesn't use any type of a gear reduction; it just spins with the exhaust pressure that is already there. A turbo feeds off itself, it uses back pressure to create boost and as it creates more back pressure it creates more boost. With out a waste gate a turbo would be more then happy to make 30 PSI and blow your motor.
I am probably the last person on this forum who needs any kind of forced-induction lesson. I am perfectly aware of how the systems work, and their advantages and disadvantages. But I quoted this so I could high-light your own words for use in just a moment...


A supercharger is severely limited by slipping belts and volume. A magnuson supercharger makes decent power down low but totally falls off up on top end when you try and run more then 7 PSI. Why do you think the SS Cobalt has 200 horsepower with a supercharger and the turbo Solstice will have 245 horsepower with the exact same motor???
Now, this is where your weakness lies - your knowledge of superchargers is about as deep and impressive as the McDonalds receipt I just threw in the garbage. Firstly, slipping belts is a totally unrelated problem that has nothing to do with power output and is about as relavent as putting a potato in a turbo - which is to say completely irrelevant to the topic at hand. If you have either one of those situations, fix it. Secondly, magneson superchargers do not "totally fall off up on top" when running more than 7 psi. The "problem" is heat soak caused by the blowing rather than compressing of the roots blower (since a roots design isn't really a compressor, per se). Simply put, adding an intercooler to both applications in the comparison completely evens out the playing field again. I run ~11-12 PSI every day on my eaton, non-intercooled, no problems. GTP people have found that this is about the cutoff before seeing heat-soak. Furthermore, PSI is definately not the standard of measuring power coming out of an engine and your reliance on it as the benchmark for the comparison is fatally flawed. I can take a roots-blown engine and only modify cams, heads, and/or exhaust and it will make more power with less PSI than it originally had. It's actually much more about flow when dealing with roots. And finally, the ecotecs are not the exact same motor, as everything about the combustion chamber is vastly different.


Essentially the supercharger needs 1.80 PSI just to get it back to where it was stock. A turbo needs .35 PSI to get it back to where it was stock.
Oh so true, but coupled with your statement that I emphasized above it becomes quiet obvious that at cruising RPMs the supercharger has no problem supplying the 1.80 PSI since it has a perfectly linear relationship with engine RPMS. While the turbo does nothing but sits there sucking away .35 PSI because it feeds off of its own load that isn't there until you get on it.

Because the turbo creates a lot of torque sooner in the power band and because it doesn't add an engine load you get better gas mileage.
No offense, but this is where you need to put down the crack pipe. Go to ANY performance car forum that uses superchargers and make the statement that "turbo creates a lot of torque sooner in the power band" and you'll get laughed out of there so fast your grandchildren will be born as starving comics. I suggest any of the multitude of Mustang/Cobra/Whipple sites if you really want to see how bad a flame-fest you can ignite.


For example the Porsche 911 Turbo gains 119 horses over a non turbo 911 with only a 3/4 MPG drop, the SS Cobalt has a gain of 55 horses over the regular Cobalt but it loses 2/5 MPGs.
And yet GTP's get better mpg than their N/A 3800 GT brethren. Since the displacement is the same on the 3800s it's a much better comparison than the Cobalt that changes out critical dimensions between engines.

Top Fuel dragsters use roots blowers because of the required volume and cost. It wouldn't be too cost effective to build a 300 millimeter turbo to handle that much power.
Riiiiiiiiiiiigghht. Because top fuel dragsters have such small budgets... But hey, since I did purposely caveat my entire previous post with "dollar for dollar" I guess that means you admit that I was right all along! Maybe you missed that "dollar for dollar" part???
:lol:


The world's fastest door slammers are turbo cars now.
Oh I'll give you this one - I've never disagree there. You were spot on when it comes to the parasitic losses, so there is no doubt that in the end, if you're trying to make a "world's fastest door slammer", or peak power is your goal (aka 1200hp supras), then a turbo (and a big bill) is probably in your future. There are many, many more factors to consider, though.

The world's fastest 4 cylinders are all turbo ecotecs.
:rolleyes: Do some more research.

Check out this graph from Hot Rod Magazine:

"Given equivalent vehicles, the turbo would easily motor away from the centrifugal in an acceleration contest......The turbo offered massive midrange torque production, the only system to exceed 600 lb-ft. Need more convincing? At 4,000 rpm, the turbo was more than 100 lb-ft. stronger than either the Roots or centrifugal." Richard Holdener, "Battle of the Boost"
For every article and graph you can post to prove your point, I can post another to prove mine. I'd LOVE to see this article, but as presented here there are just too many factors missing to say it's actually a fair comparison. The article would need to keep PSI and CFM levels comparable (since you can "turn up" boost on a turbo, let the supercharger decrease pulley sizes). And to still be unbiased, you'd have to use different cams in the comparisons since turbo and supercharged applications respond to vastly different cam specs. And just to be sure it's on the up-and-up, I'd need pulley sizes and SC model numbers to verify potential flow.

But hey, benefit of the doubt: lets take a look at what we got here. It's got pretty curves drawn there. Gee, look at that, they all are shaped pretty much like standard theoretical curves for the different types of systems. Notice how the turbo peaks high in the mid range, but has a much steeper ROA & ROD. Turbos are traditionally tuned to peak in the higher end, but more are showing up tuned for mid-range like this so the shape of the curve isn't unbelievable. The centrifugal is also peaky, just as it's always described. And the "lowly" roots blower? Nice and flat. Gee, I thought you said they fall flat up top? No sign of that here. Just a solid power curve from one end to the other. If this graph is showing any of them "falling flat up top", it's definately the turbo.

But wait! What's this? They left one out! The big-boy of superchargers isn't even represented. :lol: If anything says this comparison is biased, it's the fact that a comparison with a twin-screw wasn't done. Oh twin-screw, my lovely twin-screw, how do I love thee? Let me count the ways...

Even if this comparison was validly performed, the twin-screw would have the same flat curve that the roots has (if not flatter), with better power across the entire rpm range than the roots - and peaking at about the same hp level as the centrifugal (certainly at a more mid-range rpm). It becomes apparent that even in this comparison, had they included the twin-screw, the turbo would be overtaken by the twin-screw in both the high & low rpms. Suddenly, even in this comparison, the power-under-the-curve is threatened by the twin-screw... Wonder what it would look like...



The comparison would be even worse for the turbo if we could prove that it was somehow biased... let's see. You said yourself that you did comparisons between roots and turbos, and noticed a 16% loss per pound of boost. Assuming (uh-oh) that PSI was comparable and disregarding CFM (in other words, completely taking your idea of a roots blower, as flawed as it is) There's quite a bit more than 16% loss from the turbo to the roots on that graph. I'm gonna guess since peaks aren't labeled at a turbo peak of ~625hp and a roots peak of ~475hp, difference of 150hp - a loss of 24%. Gee, that's an extra 8% loss over what you yourself claim. I guess you can tune for a supercharger better than these guys. The next flaw in the graph is the artificial limitation of "usable" horsepower into an RPM range that favors the turbo. They really should label it "used" horsepower. I use the 1000-2500 rpm range constantly to destroy opponents from streetlight-to-streetlight. No data under 2500 RPM? Yeah... pretty graph, but worthless. And ~500hp on the turbo at 2500 RPM? Something smells in the state of Denmark...

Now after all that, somebody might think that I'm all about the supercharger and I'm a turbo hater. Nothing could be further from the truth. Turbos rule the roost when it comes to peak hp (RMTS not included, save that for another day). And because of that, turbos are great in an application where you can select that chunk of the rpm curve where nothing else can touch the turbo. Autocross and road coarses instantly jumping to the front of the list, and even daily drivers with a manual transmission fit a turbo better. Heck, most rwd cars will fit turbo systems in the engine bay easier than a supercharger.

But you fail to give credit where it's due. In applications where you can't force the RPM range (high power drag racing, streetlight-to-streetlight brawls) or IMHO even daily drivers with auto transmissions (worse gearing responds better to broader curves) suddenly the supercharger gets the kudos. But I also suggest supercharged cars for beginners in the performance world, for other reasons. Roots cars respond well to most mods that apply to N/A cars, such as headers & exhaust. Superchargers with modular pulleys are less complex to tune and much easier to control a wide array of PSI/CFM levels for the beginner. Reliability used to be much better with SC's too, although water cooled turbos have pretty much evened that out (do RMTSs use water cooled turbos?). And yes, I stand 100% by my MPG claim for superchargers. I challenge you to find any turbo at my horsepower level getting my MPG. Oh, and price. Roots & centrifugal are notoriously cheap for OEMS to produce, not to mention you don't have to have a bunch of special exhaust parts. Just use the same ones from the N/A base car. Hence the reason that GM bean counters will Ok a supercharged platform before a turbo'd one.

But in particular to this thread, which is about CA CARB, a supercharger leaves all emissions systems unmodified. Trust me when I say that CA CARB seriously frowns on any kind of modification to the exhaust since they won't like any mod at all that changes the position or distance from the exhaust ports of the CAT, the oxygen sensor, or the EGR connection. I've heard so many CA CARB vs. turbo horror stories it makes me cringe and thank the Lord that I don't have to go through that.

So, no, I'm not flat-out-wrong. The truth of the matter is that there are so many different applications and variables that the truth cannot be covered in a couple of blanket statements.
 

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Slightly off-topic

Speaking of EGR. There is none on ecotech motors. At least not on the 2.2L in my VUE. Pretty sure there's not an EGR system in the 2.4L VVT application, either. I haven't looked, though, to tell the truth :blush:
 

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Just based on first hand experience only and with blanket statements aside:

You’re right; my experience with blowers has defiantly proven that turbos are usually the better choice. The Prochargers do okay but they hit full boost way up in the RPM range. The Magnuson/Eaton blowers I have seen were terrible just because of the hot intake temperatures. Most of the Maggies had intercoolers but they were terribly insufficient. Replacing the composite intake manifold with a big aluminum air compressor was a great way to create a giant heat sink. The Intercooled Maggie GTOs I have seen run at the track were lucky to drop 2 tenths due to the computer pulling so much timing with the high intake temps. My car non-intercooled has intake temps that jump to 20 degrees above ambient at boost, I have seen GTOs registering 220 degree intake temps with the Magnuson supercharger and intercooler!

The MPG increases I have seen have been huge after turbo installs. I’m guessing it’s the reduction in manifold vacuum at cruse RPMS along with ability to stay in over drive while the turbo creates more torque sooner in the lower RPMS.
I have seen Hummer H2s go from 9 MPG to 12 MPG with Turbos. My car gets 30 MPGs on the highway which is about a 3 MPG improvement over stock. I have seen Tahoes and Suburbans pick up 20% better fuel mileage.
I have even seen Corvettes pick up 2 MPGs as well. I have actually pulled off Eaton superchargers off of TRD Toyotas and Magnuson superchargers to see huge horsepower gains and huge MPG gains with the addition of a turbo. That’s usually with the superchargers running 8PSI and going down to 5 PSI with a turbo.

Where I think you're wrong is at what RPM you think the turbo begins to make boost.
Remember a turbo makes boost based on engine load not engine RPM, which means a turbo will make boost when ever you want. At idle 850 RPMs I have about 20 inches of vacuum. At 1500 RPMs on the freeway I'm at about 5 inches of vacuum. If I do give it a bit more throttle on the freeway or if the grade increases I hit 0 inches of vacuum instantly and begin to build boost. I can make 3 PSI at 1500 RPMs while I'm on the freeway going up a hill, can your supercharger do that? As soon as I start my car the turbo whistles. I can even launch off the line at full boost if I want to by bouncing off a lower rev limiter. Launching with full boost is completely worthless due to loss of traction but with good tires it’s a great way to out launch the supercharger guys. That’s 9 PSI at 3,500 RPMS; can your supercharger do that? A properly sized turbo will perform as it should with both fast spool time and a flat power curve all the way to redline. My LS1 uses a 60-1 TO4E with .81 A/R housing,

When you’ve been involved in a few hundred turbo installations you get a pretty good picture of what’s involved.
 

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Discussion Starter · #10 ·
Crap! I just wanted to know about getting a car smogged in California with a non stock supercharger on it, and I started off the whole SC vs. Turbo debate again! :banghead: As of yet, no one has completely answered my question. Apperently there are some companies that go to the trouble to register/certify their systems with the state. Are there any of these companys that do smog legal systems for the Ecotec? If so what do they offer?
 

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To answer your question.

Every aftermarket modification from cold air intake to cat back exhaust must be certified and receive an CARB # to pass emissions in California. When you go and get your vehicle inspected and if they notice a modification they will ask you for a Carb number for that part. This has nothing to do with whether it's a throttle body spacer or full turbo system. Remember the CARB #s issued to supercharger and turbo kits is very specific. A supercharger kit for example will require the same tuning, fuel system modifications, boost level, exhaust, etc... that the orginal tested vehicle had installed. For example if you purchased a supercharger kit and want to run a bit more boost or have it dyno tuned professionally you will lose that Carb certification for that supercharger kit. If you want to run a bit larger fuel injector or a better fuel pump then you will also void your carb number.

At this point there are no forced induction systems approved for the Solstice. And no, you can not use another ecotec vehicle's carb #. Mallett's approval should be a no brainer with the previously approved Corvette LS2.

dang smog nazis!
 

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bradyb said:
The Intercooled Maggie GTOs I have seen run at the track were lucky to drop 2 tenths due to the computer pulling so much timing with the high intake temps. My car non-intercooled has intake temps that jump to 20 degrees above ambient at boost, I have seen GTOs registering 220 degree intake temps with the Magnuson supercharger and intercooler!
I'm sorry, but if this is your experience with superchargers, it's ridiculous. 2 tenths after adding an intercoolded supercharger? BS. Go tell it to the Cobra boys. Sounds to me like somebody got ripped the **** off...

I got a friend with 5 PSI on a supercharged non-intercooled CTS-V, and knocked way over 1.5 off the time, still on street tires. Hell, I'm running 11-12 PSI non-intercooled, and my intake temps are nowhere near that high.



The MPG increases I have seen...
Riiiight. Before you were saying how you knew first-hand that turbos get just under N/A mpg, and now they get 20% better mpg???

I suggest you patent it and call all the car company's because they really need to know how to increase MPG by 20%... You could be rich...

I'm sorry, but no matter how much you try to beat the horse, if the turbo isn't producing positive PSI at that very moment, it's nothing but an exhaust obstruction that is causing your engine to be less efficient than it would be N/A.

Where I think you're wrong is at what RPM you think the turbo begins to make boost.
Remember a turbo makes boost based on engine load not engine RPM, which means a turbo will make boost when ever you want. At idle 850 RPMs I have about 20 inches of vacuum. At 1500 RPMs on the freeway I'm at about 5 inches of vacuum. If I do give it a bit more throttle on the freeway or if the grade increases I hit 0 inches of vacuum instantly and begin to build boost. I can make 3 PSI at 1500 RPMs while I'm on the freeway going up a hill, can your supercharger do that?
Yes my supercharger can make 3 PSI, and more, at 1500 RPMS. Easily. You really need to get some more education on them.

As soon as I start my car the turbo whistles. I can even launch off the line at full boost if I want to by bouncing off a lower rev limiter.
As soon as I start my car, the supercharger whines. And it never stops. And I don't have to bounce off of anything to get full boost. I just have to hit the pedal. Boom it's there. Instantaneous. Any speed, any RPM, any grade, any driver. Can your turbo provide the power boost when you don't expect it? Say, in an emergency where you gotta move NOW but didn't expect it? The supercharger does...

Launching with full boost is completely worthless due to loss of traction but with good tires it’s a great way to out launch the supercharger guys.
I'm sorry, but the supercharger guys definately have the claim on launches vs turbo. Seriously, you're starting to sound like you actually believe all the STS sales propoganda. Of course, you can spool up your turbo at the line, but superchargers ('cept centrifugal) don't have to spool up anything. All they have to do is close the bypass valve, if they even have one...

Hell, my wife can get launches just as good as mine, because it doesn't take anything special for a supercharged car to launch. You'd have a hard time teaching her how to spool up a turbo to just the right amount to allow a hard launch without giving too much and spinning off the line. So there's another supercharger advantage: ease of driving.

That’s 9 PSI at 3,500 RPMS; can your supercharger do that?
Yes. Full boost just off idle. Easily. I get full 11-12 PSI boost in the split second it takes for the bypass valve to close. Would you like vid of me cruising at ~25mph and instantaneously hitting full boost and spinning tires?

When you’ve been involved in a few hundred turbo installations you get a pretty good picture of what’s involved.
Involved in turbos, yes. That doesn't mean you know diddly about superchargers.


Again, I'm not disagreeing that turbo systems make more power when you ignore all other factors, but there are soooo many other factors that the supercharger is still the preferred system in many applications.
 

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I really have seen the mileage gains by the way, it's probably one part good tuning, one part less required throttle, and one part more torque earlier in the power band.

So Sky Captain you're saying you have full boost(13 PSI) at 1000 RPMS? I would really like to see a vid of that.

My final point before I agree to disagree. If the roots/screw hybrid is the way to go why are all diesels turbo charged? Why do 03/04 Cobra guys buy turbo kits and why do S/C GP guys buy turbo kits while trashing their superchargers?
 

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I am saying that I can hit full boost just off idle ~1200rpm, 11 PSI. Sometimes I see 12 PSI at higher rpm when the situation is right. Never said anything about 13 PSI.

<*shrug*> No idea about diesels. I don't do diesel yet.
The cobra guys run more Whipples than turbos when it comes to street cars.
The Grand Prix guys run a hell of a lot more superchargers than turbos. The turbo grand prix guys are almost completely track guys trying to run 11s or less. Zoomer of zzp, the biggest supplier of grand prix go-fast parts just hit 9's, but he kept the lil ol M90 on it so he could keep his outstanding launches, and in his own words, keeping the m90 means he retains a daily driver.

Here's the video of his 9 second run...

http://portfolio.iu.edu/jdsorens/Zooomer_Runs_9_s.wmv

And the fastest GP is supercharged. Of course, its hard to call it a gp anymore, since it's been converted to rwd and runs a blown V8. 8.56 1/4

http://media.putfile.com/8-second-GTP
 

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I refuse to believe your full boost off of idle with a centrifugal.

What do you drive a diesel? You do not use the 1000-2500 rpm range to beat anyone in a race ESPECIALLY with faster cars because you're in the range for barely a second before you've accelerated out. Most manual drivers don't stop slipping the clutch until the 100% clutched engine speed is around 2500 anyway.
 

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Thraxz said:
I refuse to believe your full boost off of idle with a centrifugal.
:lol: :lol: :lol: :lol: :lol:

It's a roots. Pay attention.

:lol: :lol: :lol: :lol: :lol:
 

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Thraxz said:
What do you drive a diesel? You do not use the 1000-2500 rpm range to beat anyone in a race ESPECIALLY with faster cars because you're in the range for barely a second before you've accelerated out.
60 foot times for GTP's and similar running cars run from 1.7-2.4. They are approx. 14 feet long (IIRC). That means the difference of a 1.7 and a 2.4 or an even slower car can literally be multiple car lengths advantage by the time you get 2500 RPMs - which I do regularly.

KTHANXBYE.
 

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I would think that you would have a huge traction problem with full boost off idle with a heavy FWD car. What are you running in the 1/4 with 12 PSI? Are you using methanol injection? How much of a power increase are you averaging per PSI, with 12 PSI you're close to 1 bar.

So tell me this. If you have full boost at 1,000 RPMs how much boost do you have at redline? With the supercharger spinning in relation to engine RPMs why doesn't the boost increase? Does it just max out at 11-12 PSI?
 
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